Three-dimensional echocardiography improves accuracy and compensates for sonographer inexperience in assessment of left ventricular ejection fraction

This study was performed to determine whether 3-dimensional echocardiography (3DE) with a magnetic tracking system for image plane localization, which unlike standard 2-dimensional echocardiography (2DE), does not require acquisition of specific image planes or "standard views" for quantitative measurement of left ventricular volume and election fraction (EP), could compensate for sonographer inexperience. Eight adults underwent magnetic resonance imaging (MRI) scanning; they also had 2DE and 3DE performed by 2 experienced and 3 novice sonographers. Data were analyzed by a single expert reader blinded to patient and sonographer identity. Linear regression of MRI EF (reference standard) against echocardiographic EP yielded the following results, where RD indicates the residual difference between measured MRI values and those predicted using echocardiographic results: expert 3DE: r = 0.97, RD = 2.4%, and r = 0.96, RD = 2.8%; novice 3DE: r = 0.83, RD = 5.1%, to r = 0.95, RD = 4.8%; expert 2DE: r = 0.85, RD = 4.8%, and r = 0.86, RD = 4.9%; and novice 2DE: r = 0.34, RD = 11.7%, to r = 0.69, RD = 6.6%. Comparison of error variances indicated that novices who used 3DE equaled the performance of experts who used 2DE, although experts mere always more accurate than novices when both used the same echocardiographic method (3DE vs 3DE, 2DE vs 2DE). In a comparison of methods, 3DE was always superior to 2DE, regardless of sonographer experience. Three-dimensional echocardiography allows even novice sonographers to obtain diagnostic-quality data sets, which they were unable to accomplish with 2DE. These results suggest that scanning with 3DE, combined with remote expert interpretation, may be useful in providing echocardiographic services in regions where they are presently unavailable.